Which is the fastest-growing cancer?

FAIRFIELD, Conn. — Earlier this year, Laura Longueira locked herself in her bedroom for a week.

No, it wasn't the stress of motherhood taking its toll -- Longueira had just undergone radioactive iodine treatment for thyroid cancer, and posed a radiation risk to her family.

She couldn't be around her husband or three kids; she couldn't help out around the house; she couldn't share a bathroom.

"The first few days were the worst," Longueira, 41, recalled. "You're not even supposed to leave your room. [My family] would have to leave me a cooler with stuff to eat," she added. "I felt bad because of my kids. It was tough not being able to help them with things. I missed three of my son's baseball games."

For Longueira, it all started with a nodule -- a tiny lump on her thyroid gland in her neck -- that turned out to be malignant.

She underwent surgeries to remove the thyroid, followed by radioactive iodine treatment, or iodine-131, to eliminate remaining thyroid cells, and took medication to compensate for the functions of the excised gland.

"You gain weight, you have no energy, you're freezing," Longueira said of the effects of living without a thyroid. "I've been wearing a sweater up until now."

Longueira counts herself among the skyrocketing number of Americans diagnosed with thyroid cancer in recent years. Cases of the disease increased at a rate of 6.5 percent annually from 1997 to 2006, making it the fastest-growing cancer among women and men, according to the National Cancer Institute. More than 37,000 cases were recorded last year.

Generally, thyroid cancer has a positive prognosis -- the recovery rate for papillary thyroid cancer, the most common form, is more than 90 percent -- but the pace at which Americans, especially women, are contracting the disease has many doctors worried.

"[The trend] is disconcerting," said Dr. Sara Richer, an otolaryngologist and head and neck surgeon at St. Vincent's Medical Center in Bridgeport, Conn. "Many patients have excellent prognoses and do very well. But there's still the fact that we are diagnosing more people."

The trend has medical researchers baffled, although some propose that exposure to radiation could be the cause. A 2009 report by the International Journal of Health Services revealed an epidemic of thyroid cancer -- about 66 percent more than the national average -- in counties closest to the Indian Point Nuclear Power Plant in Buchanan, N.Y.

Better methods of detection have played a role in the increased diagnoses. This has boosted the prognosis for many individuals with thyroid cancer, even as the number of cases continues to rise.

Improved access to CAT scans and ultrasounds means "you end up finding stuff much earlier," said Robert Busch, managing partner at Endocrine Group, an endocrinology practice in Albany, N.Y. "It's very controllable and curable when found early."

Another positive development, Busch added, is that tests for unrelated issues also have led to an increase in "incidental findings" of the disease.

Such was the case for Longueira: a CAT scan for a problem with her salivary gland caught the nodule on her neck. Doctors kept an eye on the abnormality for several years, before a January biopsy determined the tumor, which was diagnosed as papillary, was expanding.

"It's kind of a scary thing, but it was found early and we've kept it under control," said Longueira, whose mother also had thyroid issues.

Situated in the neck, below the Adam's apple, the thyroid regulates the speed at which the body uses energy, makes proteins and interacts with hormones. To maintain these functions, Longueira and thousands of others recovering from thyroid cancer must take medication for the rest of their lives.

Still, while doctors remain alarmed over the spiraling rate of thyroid cancer, and keep a close watch over their patients, they are optimistic that a vast majority of people with the disease will recover.

"It's important for people to remember that . . . when cancer is diagnosed, most patients have an excellent prognosis," Richer said. "We have concern about increased incidences, but most people do very well."

Now in remission, Longueira is "feeling much better" and is hopeful about her recovery.

"I missed four months," she said. "I'm happy to be there for my family again."